Purification of ether and of other volatile substances



Fatented gept. 2, @241,

JAMES COTTON,

FONT DE NEMOURS & COMPAII OF DELAWARE.

PURIFICATION OF ETHEL-i AND OF OTHER entree stares @FFHQE.

0% TORONTO, ONTARIU, CANADA, ASSIGNOR Y, 0F WILMINGTON, DELAWARE, A CORPORATIUN to n i. no

vonamnf suns'rancns,

Application filed September 215, i918. Etc-rial No. 255,637.

To all whom it may concern Be it known that of Toronto, in

Canada, have invented a useful Improvement in Ether and of Other Volatile Substances,

declare that the following is a do hereby 1, JAMES the Province of Ontario,

H. CorroN,

certain new and Purification of and full, clear, and exact description thereof.

invention relates to a process for purifying volatile substances, such as (ethyl ether, and

pertains especlally to a process of this kind in which volatile impurities that may be present areseparated by fractional condensation.

The commercial facture of diethyl as ethyl ether, sulphuric consists in heating a mixture of hol and concentrated sulp reaction by which ether is p the subject of considerable process has been process for the manuoxide, commonly known ether, or ether,

ethyl alcohuric acid. The formed in this scientific investigation, and probably proceeds in two stages, but purposes it consists in the two molecules of alcohol for all practical abstraction from of one molecule of water as represented by the following equation;

QOJ-LOH: ((LH The mixture of sulphuric used 1s, however,

+ 2 acid and alcohol capable of forming man other products, and the formation of pro ucts other than diethyl oxide is further promoted by such conditions. as contact of the ingredients of the" mixture with the hot metal of the presence in quantities of air, purities in acid, etc.

duced is quite impure.

which the apparatus the apparatus of small secondary reactions, imthe alcohol and in the sulphuric For these reasons the ether prol f the ether isto is constructed,

be used in the arts as a solvent or for some other ordinary purposes,

simple washing with alkali or water, followed by distillation, is usually considered suliicient. lf the ether is to be used for medicinal purposes,

however, such as administration for the pun pose of producing anesthesia, it is essential that the crude ether be carefully purified.

Among desirable to remove may bementioned hydes, acetone, acids,

the impurities which it may alde- I dissolved gases,

higher wh ich ethyl ether have accompanied .scription is so pure peroxides, ethyl sulphur dioxide, fusel oil, vinyl alcohol, homologous others, etc. Some of these impurities may in themselves be very undesirable in ether which is to be used as an anaesthetic, while others may be of such a nature as to cause gradual. deterioration of the ether after it has been sealed up in a container. Because of the varied chemical nature of the impurities and the wide range of boiling points which the represent, the complete purification of t e ether by, a simple process has always been a dithcult matter.

alcohol, carbon monoxide,

The object of my'invention is to provide a convenient process through and other volatile sub stances may be easily freed from all but the merest traces of any-impurity.

Another object of dispense, as far as possible, with the use of chemical reagents, so as to thereby reduce to be maintained at a difierent temperature from the others.

The product obtained by the use of my apparatus in accordance with the method of using it outlined in the following dethat it will be found to give negative tests for impurities by all commonly known methods of analysis. It

may be stated that the best results will be obtained and the application of the process.v simplified if the ether is first subjected to a. simple purification process in accordance with some one or more of the well-known methods for the removal of the greater portion of the impurities.

While the process may becarried out in the use of my invention is to the volatile suburities which the evaporator there a condenser '8, which V being lower than that of the imme tem ierature of the last cooling various forms of apparatus, one form of apparatus which I have found to be suitable is exemplified in the following description and illustrated in the accompanying, drawscale, of three condensers of the-series, the

first condenser of Figure 1.

An annular evaporator 1 is disposed in a container 2 adapted to hold water or through which water ma be circulated. The evaporator 1 is supp ied with liquid through a pipe 3, having a valve 4. Another inlet pipe 5 with a valve 6, is provided for introducing a current of an inert gas, suchas air. From the top of leads a pipe 7 to is shaped like a funnel, and in which is nested an inverted conical member '9. The conicalmember 9 is so spaced from the conical part 8 as to form a condensin chamber; The inner conical member 9 is adapted to hold a coolin mixture. The stem 12 of the funnel-shape member is surrounded I also acts as a condenser. An outlet 13, with a valve 14, is provided in the lower part of thejacket 11, and the lower portion of this jacket is surrounded bya vessel 15 adapted to hold a refri crating mixture.

A pipe 16 lea s from the upper art of the jacket'lll to the upper part of a second condenser 8, which is similar in all respects to the condenser'8 just described. An outlet'pipe 16 leads from the condenser 8 to a thlrd condenser 8", and a third outlet pipe 16" leads from the third condenser 8" to a fourth condenser 8', all of the condensers being similar in construction.

In applying of ethyl ether, in which connection it has been found to be especially advantageous,

which is' shown in the crude or partially purified other is mixed with about 10 to 20% of its volume of pure water and maintained ata temperature at which active evaporation of the ether will occur, but below the boiling point of the ether. A current of a gas, such as air, which is inert with respect to the ether, is passed over the surface of the liquid to carry off the vapors which have formed. The vapor mixture is then cooled in. several stages, the cooling temperatureof each succeedin stage iately preceding stage. When purifying ethyl ether, the temperature of the first cooling stage is preferably about 20 0., and the stage is pref: erab ybe'tween -15 and 20 0., intermediate temperatures being employed at densed mainly by a jacket 11, which theprocess to the purificationthe respective intermediate stages. The purest ether will be obtained at the middle stage or stages, the impurities 'of higher and lower boiling points than ether being conrespectively. Any ether which may not have beencondensed at the last cooling stage may be recovered by passing the effluent from the last stage into ether-absorbing material.

The process is carried out in the abovedescribed apparatus as follows:

The evaporator 1 .is partly 'filled through the inlet plpe '3 with crude ether mixed with 10- to 20% of its volume of distilled water.

The container 2 is filled with water which is maintained at a temperature of about 25 0.,

since at this temperature ether has a consid- The vapors ofether erable vapor pressure.

carried out through which are, formed are the pipe 7 to the condenser 8 by a current of A air introduced through the pipe 5. As the air-vapor mixture passes down through the condensing chamber formed by the oppositely-disposedconical members 8 and 9,

some of the -high boiling impurities are 0 condensed and the stem 12 into That part of the air-vapor mixture which remains uncondensed passes out throu h the pass downward through oration of condensed liquid which accumulates in the bottom of the chamber 11. At suitable intervals the condensed liquid which has accumulated in the bottom of the chamber 11 is drawn off into a suitable con- 'tainer by opening valve 14.-

The uncondensed air-vapor mixture passes up through chamber 11 and through pipe 16 to the second condenser 8, where it is subjected to a lower temperature than prevailed 115 in the condenser -8. The vapor which remains uncondensed in 8" passes through pipe 10 into the supplemental coolin .chamber 11 and'out at 16 into the thir condenser 8", where the vapor is subjected 120 to a still lower temperature, and, if desirable, to one or more other condensers.-

Wherethree condensers are used, the cooling mixture which is placed in the inverted conical member 9 has a temperature of about 20 0. in the first condenser, whereas the cooling mixture in the second condenser has a temperature of about 7 0., and the cooling mixture in the third condenser a temperature of from in the first and last stages, 70

the cooling chamber 11.

pipe 10 into an intermediate portion in the er 11 serves to accumulate any drop- (not shown) through the pipe 13 of each of the condensers I together with some dissolved impurities and some ether. Tlie'condenser 8 will contain a fairly pure etherflout it will be contaminated with substances whose boiling point is below that of pure ether. The purest ether will be found in condenser 8.

described without departing tion, and that various till one,

selected has no action on containing prises evaporating the ether at a tempera- When more than three condensers are used, such as the tour condensers as shown in the accompanying drawings, the temperatures of the first and last condensers should be about the same as those above given for the first and thirdcondensers,that is, about 20 G. for the first and about 15 to -20 C. for the. last; the temperatures of the intermediate condensers will approach each other more closely than those given above, and the purest ether will be found in the condensers which are in the center of the series.

Instead of increasing the number of condensers, three condensers only may be used and the ether 8,-may be put through the process a second or a third time.

It will be understood iications may be made in the a that various modiparatus above om my invenchanges ma be made in the rocess, depehding upon the particular vo atile substance which is to be purilied and the degree of purit of the substance before being subjected to this new process. For example, some other gas may be used instead of air, so long as the gas the ether under the conditions described; the temperatures at which the condensers are maintained may be varied within certain limits and will depend, of course, in each case upon the particular vvolatile substance which is being puritied.

1 claim:

1. The process of purifying a volatile substance containing volatile impurities, which comprises evaporating the impure substance at a temperature below its boiling point, subjecting the resulting vapors to cooling in a series of well-defined stages, the cooling temperature employed at each succeeding stage being lower than the temperature of the immediately preceding stage, and separating said substance in a substantially pure state at an intermediate cooling stage.

The process of purifying ethyl ether volatile impurities, which comture below its boiling point, subjecting the resulting vapors to cooling in a series or well-defined stages, the cooling temperature employed at each succeeding stage being 1 lower than the temperature of the immedicomparatively which condenses 1n the middle to cooling in a series of stages,

ately preceding stage, and separating ether in a substantially pure state at an intermediate cooling stage.

3. The process of purifying ethyl ether containing volatile impurities, which comprises mixing the impure ether with water, maintaining the mixture at a'temperature below the boiling point of the ether but sufficiently high to cause active evaporation, subjecting vapors of said impure ether to cooling in a series of well-defined stages, the cooling temperature employed at a succeedin stage being lower than the temperature o a precedin stage, said temperatures being sufiiciently ow to condense at least some. of the impurities.

4. The process of purifying eth l ether containing volatile impurities, whic comprises mixing the impure ether with water, maintainin the mixture at a temperature below the'boiling point or the ether but suficiently high to cause active evaporation, carrying away the vapors by a current'otan inert gas, and subjecting the resulting vapor mixtureto frictional condensation.

5. The process of purifying ethyl ether containin volatile impurities, which comprises ad 'ng water thereto, passing a current of air in contact with the liquid to evaporate the ether, and subjecting the airvapor mixture to coolin in a series of welldefined stages to cause lr-actional condensation, the temperature of the first stage being about 20 C. and that of the last stage from about -15 to -20 C.

6. The process of purifying containin volatile impurities, prises ad ing water thereto, passin a current or" air in contact with the liqui while maintaining the latter at a temperature below the boiling point. of the ether, to evaporate the ether, and subjecting the air-vapor ethyl ether mixture to cooling in a series of well-defractional condensafined stages to cause first stage being tion, the temperature of the which com-' about 20 C. and that of the last stage from about ---15 to -20 C.

7 The process of purifying ethyl ether containing volatile impurities, which comprises passing a current of air in contact with impure ether containing from about 10 to 20% of its volume of water and maintained at a temperature of about 25 6., and subjecting the resulting current of air and ether vapor temperature employed at a succeeding stage being lower than the temperature of a pre ceding stage, said temperatures being sufficiently low tocondense at least some or" the impurities.

the cooling 8. lhe process of puriifying ethyl ether containing volatile impurities, which comprises passing a current of air in contact with impure ether containing from about 10 to 20% or its volume oi water and maintained ate temperature of about 25 (3., and In testimony that I claim the foregoing subjecting the resulting current of air and I have hereunto set my hand. ether vapor to cooling in a series of stages,

- the degree of cooling being suflicient to cause 5 condensation of substantially pure ether Witnesses only at one stage and condensation of impurities at other stages.

JAMES HENRY COTTON.

P. E. .STRICKLAND, F. H. MCCORMICK. A 

